How to check for and clear internal airlocks?

If you have no water coming from the cold water tap in your kitchen sink, there may be an issue with the public water mains in your area, e.g. a burst. If this is the case please Callsave 1850 278 278 and we will investigate. If you are experiencing supply issues during or following an outage, please visit our supply page for tips and advice.

However if the cold water tap in your kitchen sink is working but the hot water tap does not and/or none of the taps in your bathroom sinks are working, then it is likely you have an internal airlock within your plumbing system. This section outlines some practical advice which may help clear an airlock.

Firstly, make sure all the hot taps in the house are turned off.

Depending on the type of tap in the kitchen, please follow either Option 1 or Option 2 below:

OPTION 1: Separate hot and cold taps in the kitchen

If the hot and cold taps in the kitchen are separate i.e. not combined in a mixer tap, the hot tap should be turned on. If there is an airlock, no water will come from the hot tap. To clear the airlock please follow the steps below:

1. Turn off both taps

2. Connect both taps with a hose

3. Turn on hot tap first and then cold tap.

Turning on the cold tap will result in the cold water being forced through the hot water system and this will force the air which is causing the airlock back into the water tank in the attic.

4. Let the cold tap run for 1 – 2 minutes, then turn off both taps & remove the hose.

5. Let the hot tap run for 1 – 2 minutes to confirm that the air lock is cleared.

If the air lock is not cleared, repeat the procedure one or two times more.

If this is not successful, contact a plumber to correct the problem. In rare cases the cold water taps in wash hand basins or the bath may also be air locked. This procedure will also work for them but is more difficult as a long length of hose is necessary from the kitchen cold tap to the nearest wash hand basin or bath tap.

OPTION 2: Combined/mixer tap in the kitchen

If there is a mixer tap in the kitchen, please follow the steps below:

1. Turn on the hot tap.

2. With a cloth in your hand (to help reduce water squirting out) block the tap and turn on the cold water tap gently.

This should force the cold water back through the hot water system, forcing the air into the water tank in the attic. Care should be exercised when doing this in case of accidental scalding with hot water.

3. Let the cold tap run for 1 – 2 minutes, then turn off both taps.

4. Let the hot tap run for 1 – 2 minutes to confirm that the air lock is cleared.

If the air lock is not cleared, repeat the procedure one or two times more.

If this is not successful, contact a plumber to correct the problem. In rare cases the cold water taps in wash hand basins or the bath may also be air locked, this procedure will also work for them.